Compressed natural gas (“CNG”) is natural gas (composed primarily of methane) that is stored at high pressure. CNG can be used in place of gasoline and diesel fuel in internal combustion engines and is becoming more popular as a source of fuel for automobiles and other vehicles. There are many advantages to CNG. For example, CNG generally emits fewer pollutants and costs less than gasoline and diesel fuel.
The cost of and space required for CNG storage tanks have been obstacles to creating more CNG facilities for automotive and other vehicle uses, particularly in urban environments. CNG is generally compressed to less than one percent of the volume it occupies at standard atmospheric pressure. It is typically stored under high pressure in containers which undergo repeated pressure and temperature cycling. Thus, it is important for CNG storage vessels to be strong, leak proof and able to reliably contain a high volume of natural gas that can be compressed at high pressures.